Public hearing to be held about proposed changes to groundwater standards

From the press release from the N.C. Department of Environment and Natural Resources:

RALEIGH – The state Division of Water Quality and Environmental Management Commission will hold a public hearing later this month to gather input on three proposed options to change the groundwater standard for 1,1-dichloroethylene – changes that could impact the way the division establishes water quality standards in the future.

The public hearing will be held on May 23 in Raleigh in the Archdale Building Ground Floor Hearing Room, located at 512 N. Salisbury St. The hearing will begin at 6:30 p.m.; registration for speakers will begin at 6 p.m. Written comments can also be submitted to: Sandra Moore, Water Quality Planning Section, 1617 Mail Service Center, Raleigh NC 27699-1617, or by email to sandra.moore@ncdenr.gov. The comment period ends July 2, 2012.

A chemical compound used in the production of vinyl chloride and semiconductors, 1,1-dichloroethylene has a state groundwater quality standard of 7 micrograms per liter (as a frame of reference, one microgram per liter is similar to one second of time in 32 years). Recent research has determined that the current standard is more stringent than is needed for the protection of human health. The U.S. Environmental Protection Agency has updated its Integrated Risk Information System – or IRIS – at http://www.epa.gov/IRIS/ to reflect the new research. Use of the new data yields a human health protective standard at 350 micrograms per liter.

However, under North Carolina groundwater quality standards regulations, DWQ and the EMC must use the most stringent assessment of health risk as published in several resources, including the EPA’s maximum contaminant level or MCL. Currently, USEPA’s MCL for 1,1-dichloroethylene is 7 micrograms per liter.While USEPA has stated that the less stringent level is protective of human health, it has not changed the MCL due to competing workload priorities, the administrative costs associated with rule-making and the burden on states and the regulated community to implement any regulatory change that resulted.

Therefore, the Division of Water Quality is proposing three options for changing the standard, to reduce the burden for manufacturers while still being protective of human health.
Option 1: A change in the 1,1-dichloroethylene standard from 7 micrograms per liter to 350 micrograms per liter is proposed in order to incorporate the most recent U.S EPA health effects information as published in the Integrated Risk Management System at http://www.epa.gov/IRIS/ .
Option 2: A change in the criteria used to establish a standard is proposed in order to allow the EMC to establish a standard less stringent than the federal maximum contaminant level when the MCL is not established using the most recent USEPA IRIS health effects information.
Option 3: A change in the rules governing variances to allow the Environmental Management Commission to issue a statewide variance to the rules and clarify the existing variance requirements.
In addition, the EMC is seeking public input on proposals that allow flexibility in implementing the current regulations for establishing groundwater quality standards. All proposals must maintain or achieve appropriate water quality and public health standards. If a proposal generates a substantial change from existing rules additional rule-making may be required prior to adoption.

For more information, including a summary of the options and the proposed rule changes, visit the DWQ website at http://portal.ncdenr.org/web/wq/groundwaterrulesrevisions.


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